New substituted phthalazones and proc-



United States. Patent 3,017,411 NEW SUBSTITUTED PHTHALAZONES AND PROC- ESS FOR THEIR PREPARATION Heinz-Joachim Engelbrecht, Dessau, Dieter Lenke, Rodleben, and Hildegard Miiller, Dessau, Germany, assianors to VEB Deutsches Hydrierwerk Rodlehen, Rodleben,

Germany No Drawing. Filed July 23, 1958, Ser. No. 750,308

Claims priority, application Germany Aug. 15, 1957 11 Claims.

The present invention relates to certain N-substituted phthalazones and to a process for the preparation of the same. More particularly, the'compounds of this invention contain basic substituents on the amine nitrogen of the phthalazone and may be represented by the general formula ,0 Inthis formula R is an aryl or aralkyl group, which, if desired, may be substituted in the nucleus; R is bivalent straight or branched aliphatic chain with atlea st 2 and at the most carbon atoms; R and R are low molecular weightaliphatic groups, which may be closed to form a heterocyclic ring; and X is hydrogen or halogen bonded to the benzene nucleus. More particularly, R is an aryl or aralkyl radical which may contain up to 4 rings in the nucleus preferably monocyclic or bicyclic and which may contain a variety of substituents, such as alkyl, halogen, hydroxy or alkoxy, etc.; R is a bivalent straight or branched chain aliphatic hydrocarbon group containing from 2 to 5 carbon atoms; and R and R are monovalent or divalent aliphatic hydrocarbon groups, divalent ether linked aliphatic hydrocarbon radicals or divalent nitrogen linked aliphatic hydrocarbon radicals, wherein when R and R are divalent radicals, they are joined at their terminal ends to form a heterocyclic nucleus.

The new compounds are obtained in accordance with this invention by reacting a phthalazone of the general formula preferably in the form of its alkali metal compound with a haloalkyl amine of the general formula Rs t H8.lRz-N R4 In these formulae Hal represents a halogen atom, while R R R 'a'ndR have themeaning given above.

A variety of phthalozones may be used as starting materials for the present process. Among these may be mentioned: -4-phenylphthalazone, 4-m-cresylphthalaione, 4-a-naphthylphthalazone, 4-benzylphthalazone, 4-benzyl- -6(7)-chlorphthalazo ne, 4-p-brombenzylphthalazone, 4-0- methoxybenzylphthalazone, 4 p-isopropoxybenzylphthalazone.

' ,Various haloalkyl amines condensation reaction. Included among these are: dimethylaminoethylchloride, diethylaminoethylchloride, piperidinoethylchloride, pyrrolidinoethylchloride,. morpholinoethylchloride, l-dimethylamino-3-chlorpropane, 2-dimay be used for the present- 'phthalazones are The residue is washed with acetone and dried at 110 volume of toluene. The suspension 3,017,411 Patented Jan. 16, 1962 "ice preferably sodium amide, are added under stirring and In doing so, the alkali metal compounds of the formed. It is recommended that the reaction mixture be heated for some time after addition of the sodium amide, to a moderately elevated temperature, preferably between 5080 C., until the ammonia generation ceases. Subsequently, the haloalkyl amine is added at room temperature or moderately elevated temperature. The reaction is carried to completion by heating for several hours at the boiling temperature of the solvent. It is also feasible to dissolve the phthalazone and the haloalkyl amine in the solvent and then add the sodium amide, advantageously at moderately elevated temperature, for example, 40-SO 0. Also in this case, the reaction is completed by subsequent heating. It is also possible to carry out the reaction in such a manner that the phthalazone is first converted into its alkali metal salt by means of aqueous or alcoholic caustic alkalis. This alkali salt is then isolated in the ordinary manner, wherea fter, suspended in the mentioned solvents, it is heated with the haloalkyl amines while stirring, so as to cause the reaction to take place.

The reaction product is worked up in the usual manner, for example, by washing the reaction liquor with diluted cooling.

sodium bicarbonate solution and saturated NaCl solution.

for this invention are known or are obtainable according to known processes, for example, by condensation of hydrazine with o-benzoylbenzoic acid, and m-tolyl-o-benzoic acid, benzalphthalide, p-chlorobenzalphthalide, p-methoxybenzalphthalide, naphthobenzalphthalide, etc.

The compounds which are obtained in accordance with this invention have not been described in the literature.

They are valuable pharmaceutical compounds which exhibit a strong histaminolytic, spasmolytic and localanaesthetic effect. Of particular importance is the very considerable, specific and long lasting anti-histaminic effect exhibited by these new compounds. They are -very much different in their constitution from known compounds having similar effects. Consequently, they constitute a new type of highly efficient anti-histamines. They may also be used for the production of penicillin salt having a lasting effect.

- The following examples are further illustrative of the present invention, and it will be understood that the invention is not limited thereto:

Example 1 A solution which consists of 236 parts by weight of 4-benzylphthalazone, 5.6 parts by weight of caustic potash, 200 parts by volume of water and 50 parts by volume of ethyl alcohol, is concentrated by evaporation to dryness. C. 14.8 parts by weight of the thus obtained potassium salt of 4-benzylphthalazone are suspended in parts by thus obtained is gradually admixed at C. with 8.2 parts by weight of 13- diethylaminoethylchloride, whereafter the heating is continued for several hours under vigorous stirring and reflux cooling. After cooling, 100 parts by volume of water are added. The aqueous layer is separated from the toluene layer, and the toluene layer is shaken with water and 3% sodium bicarbonate solution. Upon drying the distilling 011 the toluene, 15.1 parts by weight of 2-(,B- diethylaminoethyl) 4 benzylphthalozone 1) (boiling point at 0.1 mm. Hg 208-214 C.) are obtained, whose hydrochloride melts at 142-143" C.

In analogous manner one obtains from the potassium salt of 4-benzylphthalazone and fi-dimethylaminoethylchloride the compound 2-(,B-dimethylaminoethyl)-4-benzylphthalazone-(l) (B.P. at 0.1 mm. Hg 215-222 C.),

the hydrochloride of which melts at 178 C. The methiodide of the base melts at 200 C.

In an analogous manner one obtains from 24.3 parts by weight of potassium salt of 4-benzylphthalazone and 13 parts by weight of 1-dimethylamino-3-chloropropane, 20.6 parts by weight of 2-(3-dimethylaminopropyl)-4- benzylphthalazone-( 1) (B.P. 218C.) whose hydrochloride melts at 173-174" C.

Example 2 22.2 parts by weight of 4-phenylphtha1azone were suspended in 300 parts by volume of toluene. parts by weight of finely powdered sodamide under toluene was added while stirring the mixture. The mixture was heated then to a temperature of 90 C. and until the evolution of ammonia ceased. In the course of a half an hour one then adds, dropwise, parts by Weight of fl-diethylaminoethylchloride, and boils several additional hours under reflux. After cooling, and the application of suction, the solution is washed 2 times with a saturated NaCl solution and dried over sodium sulfate. After distillation 18.6 parts by weight of Z-(fi-diethylaminoethyl)-4-phenylphthalazone-(1) are obtained (B.P. 225-230 C.), whose hydrochloride melts at 198 C.

In an analogous manner, from 30.4 parts by weight of 4-p-chlorobenzylphthalazone, F. 218 C. (prepared by the reaction of p-chlor-phenylacetic acid and phthalic anhydride in the presence of sodium acetate and the subsequent condensation of the resulting p-chlorobenzalphthalide (F. 150) with hydrazine) and 16.7 parts by weight of fi-dimethylaminoethylchloride, 26.3 parts by weight of 2 (13 dimethylaminoethyl) 4 p chlorobenzyl-phthalazone-(l) is obtained (B.P. 215-220 C.) whose hydrochloride melts at 248 C.

In the same manner, from 4-p-propoxybenzylphthalaz0ne-( 1), F. 190 0., (prepared by the reaction of ppropoxyphenylacetic acid with phthalic anhydride in the presence of sodium acetate and finally the condensation of the resulting p-propoxy-benzalphthalide, F. 99-100 C., with hydrazine) and fl-dimethylaminoethylchloride, the 2 3 dimethylaminoethyl 4 p propoxy benzylphthalazone-(I) is obtained, whose hydrochloride melts at 142C.

Example 3 26.6 parts by weight of 4-p-methoxybenzylphthalazone, F. 196 C. (prepared by the reaction of p-methoxyphenylacetic acid with phthalic anhydride in the presence of sodium acetate and finally the condensation of the resulting methoxybenzalphthalide, F. 148 C., with hydrazine),

400 parts by volume of toluene and parts by weight of ,B-dimethylaminoethylchloride hydrochloride were added to 13 parts by weight of powdered sodamide at a temperature of 40-50 C., and while stirring. This was then boiled under reflux for several hours. After completion of the reaction, the reaction mixture was cooled and water was added to it. The water layer was separated from the toluene layer and the latter was shaken with dilute HCl. From the toluene unreacted starting material was recovered after drying and distillation of the solvent. The HCI solution was treated with caustic soda and the base which separated was taken up in ether. After drying and distillation of the ether, there is obtained 23 parts by weight of Z-(fl-dimethylaminoethyl)-4-p-methoxybenzy1- phthalazone-(1) (B.P. 220-223 C.), whose hydrochloride melts at 202-203 C.

In an analogous manner, from 4-isopropoxybenzylphthalazone and l3-morpholinoethylchloride the 2-(13- morpholinoethyl)-4-isoproxybenzylphthalazone-( 1) is obtained, whose hydrochloride melts at -101" C.

Analogously there is obtained from 49.5 parts by Weight of 4-benzyl-6(7)-ch1orphthalazone, F. 163 0, (prepared by the reaction of phenylacetic acid with 4-chlorphthalic anhydride and finally the condensation of the resulting benzal-chlorphthalide, F. 156-157 C., with hydrazine) and 21 parts by weight of B-dimethylaminoethylchloride, 29.7 parts by weight of Z-(fi-dimethylaminoethyl) -4- benzyl chlorphthalazone (1) B.P. 230-240 C.), whose hydrochloride melts at 203-204 C.

While the invention has been described with particular reference to specific embodiments, it is to be understood that it is not limited thereto, but is to be construed broadly and restricted solely by the scope of the appended claims.

What is claimed is:

1. 2-( 8-diethylaminoethyl)-4-benzylphtha1azone-( 1).

2. 2- fi-dimethylaminoethyl) -4-benzylphtha1azone-( 1).

3. 2-(3 dimethylaminopropyl)-4-benzylphthalazone- (1).

4. 2- B-diethylaminoethyl) -4-phenylphthalazone-( 1) 5. 2-(5 dimethylaminoethyl) 4 p propoxy-benzylphthalazone-( 1).

6. 2-(e-dimethylaminoethyl) 4 p methoxybenzylphthalazone-( 1).

7. Z-(B-morpholinoethyl) 4 isoproxybenzylphthalazone-( 1).

8. As a composition of matter an N-substituted phthalazone of formula References Cited in the file of this patent UNITED STATES PATENTS 2,837,522 Bach er al. June 3, 1958 FOREIGN PATENTS 490,069 Belgium Nov. 1, 1949 .OTHER REFERENCES I Marly: ChemicalAbstracts, vol. 51 (1957),co1umn Simpson: Chemistry of Heterocyclic Compounds, Condensed Pyridazine and Pyrazine Rings (Interscience, 1953), pages 82-3.

Fieser: Organic Chemistry (third edition), 1956,ipages 228-9.

Hellman et al.: Chemische Berichte,

598 vol. 89 (1956), page 

7. 2-(B-MORPHOLINOETHYL) - 4 - ISOPROXYBENZYLPHTHALAZONE-(1).
 8. AS A COMPOSITION OF MATTER AN N-SUBSTITUTED PHTHALAZONE OF FORMULA 